During trunking communication, when a group call is established, base stations in which members in a group are distributed usually allocate the group call shared channels and power resources required during trunking communication.
During the implementation of the present disclosure, inventors found following problems in the prior art. If members in one group are distributed in a plurality of base stations and some base stations are adjacent co frequency base stations, large co-channel interference between adjacent co frequency base stations in which the members in the group are distributed may be caused because of the omnidirectional emission of downlink power during the trunking communication. Accordingly, interference avoidance between adjacent co frequency base stations is required. An effective interference avoidance method refers to channel avoidance between adjacent co frequency base stations. That is, if some channels of base stations in which members in a group are distributed have been allocated as trunking shared channels, channels of adjacent co frequency base stations of these base stations cannot be allocated as trunking shared channels to perform avoidance. If a trunking group is established and base stations in which members in the trunking group are distributed include a plurality of co frequency base stations, channel avoidance is required between adjacent co frequency base stations. However, because channel resources of base stations are limited, it is possible that a certain co frequency base station is unable to allocate a trunking shared channel in order to avoid a shared channel of an adjacent base station. At this time, the establishment of the group call is failure and the group capacity of a trunking system is decreased.